INVESTIGATION OF SURFACE ROUGHNESS OF STAINLESS STEEL- INOX 304 DURING ELECTROPOLISHING WITH ADDITIVES

Abstract

The electropolishing method has been widely applied to enhance the surface smoothness of stainless steel materials. However, safety concerns during the polishing process are of particular importance, as the electrolytes used typically contain high concentrations of strong acids, such as sulfuric acid (H₂SO₄) at 35 wt.% and phosphoric acid (H₃PO₄) at 50 wt.%. Therefore, this study focuses on determining the optimal composition of electrolyte components and appropriate polishing conditions to improve surface treatment efficiency while ensuring workplace safety. The results identified a suitable electrolyte solution and an optimal polishing temperature range of 30–50°C for stainless steel 304. Specifically, when adding the chromium oxide (CrO₃) additive, despite reducing the H₂SO₄ concentration to approximately 20 wt.%, the surface roughness achieved was significantly low (Ra = 0.075 µm). Furthermore, by incorporating the Glycezyl additive, even though the H₂SO₄ and H₃PO₄ concentrations were simultaneously reduced to 24. wt% and 18. wt%, respectively—considerably lower than those used in previous studies—the achieved surface roughness remained comparable, with Ra reaching 0.118 µm.